Certain electronic devices and circuits employ current regulators to provide a relatively constant current. Electronic devices and circuits such as computers, televisions, mobile devices, wireless devices, illumination devices, phase lock loops, motors, and/or the like, may benefit from current regulation. For example, current regulation may be employed to maintain a substantially constant illumination intensity or color from an illumination device, to provide a substantially constant frequency output from a phase lock loop, to regulate the speed of a motor, and/or the like.
In certain applications, it may be beneficial to selectively regulate a current at different values at different times. For example, such selectable regulation may be employed to enable an illumination device to provide multiple intensity levels, to enable a motor to run various speeds, to enable a microprocessor to process instructions at differing frequencies, to enable a wireless device to transmit at multiple power levels, and/or the like. Embodiments of the invention may be employed in these and other applications.